Method for Operating an Eye Tracking Device for Multi-User Eye Tracking and Eye Tracking Device

1. A method comprising: capturing a first set of one or more images; determining a value of a user search parameter based on one or more numbers of detected users in the first set of one or more images; capturing a second set of a plurality of images; classifying, based on the user search parameter, each of the second set of the plurality of images into one or more of a plurality of states comprising a user search state and an eye tracking state, wherein a first one of the second set of the plurality of images is classified into the eye tracking state without being classified into the user search state and a second one of the second set of the plurality of images is classified into the eye tracking state and is classified into the user search state; performing, for each of the second set of the plurality of images classified into the eye tracking state, eye tracking upon a representation of a detected user; and searching, in each of the second set of the plurality of images classified into the user search state, for a representation of user.

2. The method of claim 1 , wherein the user search parameter is based on a number of currently detected users.

3. The method of claim 2 , wherein a particular one of the second set of the plurality of images is less likely to be classified into the user search state when the number of currently detected users is greater.

4. The method of claim 1 , wherein the user search parameter is based on an average number of detected users over a predetermined time period associated with capturing the first set of one or more images.

5. The method of claim 4 , wherein a particular one of the second set of the plurality of images is less likely to be classified into the user search state when the average number of detected users over the predetermined time period is less.

6. The method of claim 1 , wherein the user search parameter is based on a variation in the number of detected users over a predetermined time period associated with capturing the first set of one or more images.

7. The method of claim 6 , wherein a particular one of the second set of the plurality of images is less likely to be classified into the user search state when the variation in the number of detected users over the predetermined time period is less.

8. The method of claim 1 , wherein a particular one of the second set of the plurality of images is classified into the eye tracking state when there are one or more detected users in the first set of one or more images.

9. The method of claim 1 , further comprising performing, for the particular one of the second set of the plurality of images classified into the eye tracking state, eye tracking upon multiple representations of multiple detected users.

10. The method of claim 1 , wherein performing, for a particular one of the second set of the plurality of images classified into the eye tracking state, eye tracking upon a representation of a detected user is based on a spatial portion of the particular one of the second set of the plurality of images classified into the eye tracking state.

11. The method of claim 1 , wherein searching, in a first one of the second set of the plurality of images classified into the user search state, for a representation of a user includes searching a first spatial portion of the first one of the second set of the plurality of images classified into the user search state.

12. The method of claim 11 , wherein searching, in a second one of the second set of the plurality of images classified into the user search state, for a representation of a user includes searching a second spatial portion, different than the first spatial portion, of the second one of the second set of the plurality of images classified into the user search state.

13. The method of claim 1 , wherein a resolution or an illumination of the capturing the second set of the plurality of images is based on the classifying.

14. An apparatus comprising: an imaging system configured to capture a first set of one or more images and a second set of a plurality of images; a processor configured to: determine a value of a user search parameter based on one or more numbers of detected users in the first set of one or more images; classify, based on the user search parameter, each of the second set of the plurality of images into one or more of a plurality of states comprising a user search state and an eye tracking state, wherein a first one of the second set of the plurality of images is classified into the eye tracking state without being classified into the user search state and a second one of the second set of the plurality of images is classified into the eye tracking state and is classified into the user search state; perform, for each of the second set of the plurality of images classified into the eye tracking state, eye tracking upon a representation of a detected user; and search, in each of the second set of the plurality of images classified into the user search state, for a representation of user.

15. The apparatus of claim 14 , wherein the user search parameter is based on at least one of a number of currently detected users, an average number of detected users over a predetermined time period associated with capturing the first set of one or more images, or a variation in the number of detected users over the predetermined time period.

16. The apparatus of claim 14 , wherein the processor is configured to search, in a first one of the second set of the plurality of images classified into the user search state, for a representation of a user by searching a first spatial portion of the first one of the second set of the plurality of images classified into the user search state.

17. The apparatus of claim 16 , wherein the processor is configured to search, in a second one of the second set of the plurality of images classified into the user search state, for a representation of a user by searching a second spatial portion, different than the first spatial portion, of the second one of the second set of the plurality of images classified into the user search state.

18. The apparatus of claim 14 , wherein a resolution of a camera of the imaging system or an illumination of a light source of the imaging system is based on the classifying.

19. A non-transitory computer-readable medium encoding instructions which, when executed, cause a processor to perform operations comprising: capturing a first set of one or more images; determining a value of a user search parameter based on one or more numbers of detected users in the first set of one or more images; capturing a second set of a plurality of images; classifying, based on the user search parameter, each of the second set of the plurality of images into one or more of a plurality of states comprising a user search state and an eye tracking state, wherein the user search state is associated with a first one or more numbers of detected users in the first set of the one or more images, wherein a first one of the second set of the plurality of images is classified into the eye tracking state without being classified into the user search state and a second one of the second set of the plurality of images is classified into the eye tracking state and is classified into the user search state; performing, for each of the second set of the plurality of images classified into the eye tracking state, eye tracking upon a representation of a detected user; and searching, in each of the second set of the plurality of images classified into the user search state, for a representation of user.